$ \dfrac{6}{9} \div \left(-\dfrac{9}{3} \div -\dfrac{7}{8}\right) = {?} $
First, we can simplify the problem: $ \dfrac{2}{3} \div \left(-3 \div -\dfrac{7}{8}\right) = {?} $ Dividing by a fraction is the same as multiply by the reciprocal of that fraction. $ = \dfrac{2}{3} \div \left(-3 \times -\dfrac{8}{7}\right) $ $ = \dfrac{2}{3} \div \left(\dfrac{-3 \times -8} {1 \times 7}\right) $ $ = \dfrac{2}{3} \div \dfrac{24}{7} $ $ = \dfrac{2}{3} \times \dfrac{7}{24} $ $ = \dfrac{2 \times -7}{3 \times -24} $ $ = \dfrac{14}{72}$ Simplify: $ = \dfrac{7}{36}$